一个MD5加密文件，代码的书写非常规范，很容易理解和分析-An MD5 encrypted files, writing of the code is very standard, very easy to understand and analyze

Java 实现DES文件加密、MD5获取数字签名和文件验证、RSA签名加密。分为接收端和发送端。-Java implementation of the DES file encryption, MD5 obtaining digital signatures and document verification, RSA signature encryption. Into the receiver and transmitter.